First post

Great website, finally registered after months of viewing forums.

I have a 2001 f150 screw 4x4 and I have never had any problem with my electric 4x4 shift until today, it will not engauge into 4x4 but when it did it went in with a loud bang and came out the same way. I did some research and I am finding out that there is an actuater on the transfer case that needs to be lubricated that may be stuck or faulty. I use the electric shift on a regular basis.

Any help would be greatly appreiciated

Past Fords
83 Ford Bronco
90 Ford Mustang Cobra
98 F-150 STX
98 Ford Expedition

 

oh yeah I forgot, location of the acuator and pics would be great.

 

The electric shift on the fly has no lube points on the t-case. If you are shifting into 4x4 when the rear wheels are sinning then there will be a great bang when the front wheels are forced to spin at the same speed as the already spinning rear wheels. If the front axle is slow to engage because of a lazy shift motor or a vacuum leak in the system it will also cause the bang.

JMC

 

Thanks, it is probably a lazy shift motor, I have had the truck for 3 years and use the 4wd on a regular basis and it only started acting up last week.

Are there any electrical connections that may be corroded causing the shift delay or no shift at all?

Thank you all in advance

 

First thing to do is to get it to act up so it can be diagnosed properly. Do the 4x4 light come on? To eliminate the T-case lift the front wheels off the ground and engage 4x4. The front drive shaft should not turn. If it does then the problem is most likely with the t-case and controls. If it doesn't turn then the t-case is engaged and the problem is with front axle lock up. There are two GEM controlled vacuum solenoids on the firewall behind the battery. They control front axle lock up. In 4x2 the one closest to the engine allows vacuum to flow to the front axle actuator motor and keeps the shift fork disengaged. When 4x4 is commanded the vacuum from this solenoid is ported to atmosphere and vacuum from the one closest to the fender allows vacuum to flow to the motor and this moves the shift fork and engages the front axle. The first thing to check is vacuum to these solenoids.

JMC

 

The 4x4 light comes on the dash but 4wd is not engaged at all or it will delay going into 4x4 and delay going back into 2wd.

I will check the vacuum to those solenoids.